Hello, I just installed the Halo mod LED taillights and hyperflash harness on my 2004 C5. These are amazing lights and are really great. But, if I put on the hazard lights this triggers the service Traction control/Active handling warning light to come on. Shutting off the car clears the warning and normal driving does not trigger this again unless the hazards are turned on again. Very odd. Any thoughts or suggestions are appreciated. Thanks.

 

I tried LED tail lights and all kinds of weird electrical Gremlins. Never did sort it out and went back to OEM bulbs (I have LED strips and switchbacks which work just fine)

 

Take a look at this thread. It's basically describing the same issue (in addition to other problems he was having, so filter out the rest ).

The link I just gave you is actually linking to a 2nd thread that has more details and goes deeper into this. After you read the 1st one, don't forget to continue to the 2nd.

 

Thank you both for the info...should have researched this before buying these lights. My bad. Anyway, it looks like I go back to the OEMs or try to add resistors. If adding resistors does the trick I would still need to test the ATC to ensure it is working properly...hmm. I need to shop for the correct resistors.

 

Please, come back and post your findings. Sadly, they never did it in the links I gave you.

 

I also had ATC messages when I first tried LEDs in my rear tails.

These are what I used with success. But testing later showed that using two, rather than four worked just as well. I didn't test using only one, but that may be enough.

Be sure to screw these onto the metal bar behind/below the tail lights to help dissipate the heat from the resistors.

Jim

 

Jim, this is excellent info; thanks so much. I will give this a try and let the group know the outcome. Much appreciated everyone. Dom

 

with what's mentioned regarding how to install the resistors to dissipate heat.

Take a look at this post for a discussion about how many resistors, considering their value and wattage. Definitely they need to be installed in a symmetric way: either 1 per side, or 2 per side, etc.

 

Jim, this is excellent info; thanks so much. I will give this a try and let the group know the outcome. Much appreciated everyone. Dom

 

Thanks, GCG. Yes, saw that thread and will review it again as well.

 

According to what was discussed in that thread, using 6 ohms resistors would require to install 4 of them, in a 2 per side arrangement.

Consequently, to install just 2 resistors (1 per side) they would need to be 4 ohms at the most.

 

I did install 4 at first but later disconnected 2 (one per side) and everything worked just as well.

 

That's good to know

In that thread we were trying to emulate the design of the LED Halo Taillights (8 ohms resistors, 2 per side for a total of 4).

 

Ok friends...here is my update on the Halos and resistors.

My C5 is 2004; with the 4 HALO LEDs tail lights and 1 new LED 3rd brake light. I have also installed the hyperflash harness.

1) installing the LED 3rd brake light with 4 OEM incandescent bulbs did not affect the brake light function. (however at the time I installed only this light, I never thought about any interference with the Flahers/ATC.)

2) I then added the 4 HALOs and the ATC codes kept triggering once the flashers were activated.

3) I then added 1 6-ohm, 50 Watt resistor to 1 brake light, and this DID NOT correct the ATC code from triggering.

4) Then, 1 at a time, I added a 2nd, 3rd, and 4th resistor (all identical ratings) --- neither 1, 2, 3, or 4 resistors in total corrected the ATC code issue.

So...I am at loss here. My understanding is that adding 4 6-ohm resistors to the brake/signal circuit results in bringing the total resistance up by about 1.5 ohms. Apparently, this is NOT enough of a load to stabilize the circuit.

Finally - from the wiring diagrams I have found, the Driver side (L) color code is Blk = ground, Brown = tail light, yellow = Brake/signal. Passenger side (R) color code is Blk = ground, Brown = tail light, green = Brake/signal.

I have all of my now-installed 4 resistors spliced into the Black and either Yellow or Green wires, for the Driver and Passenger sides, respectively.

If anyone has further info, I would be most grateful. At this point, I may swap out the 6 ohm resistors for 8 ohms each. And, if anyone knows the Wattage (power) for the circuit we can more accurately select the right value resistor.

Ugh...

 

Oh... one other thing: I added 1 OEM incandescent bulb to 1 socket with the remainign 3 LED HALOs in place, and a resistor on all 4 lamp....NO improvement of change in ATC code behavior.

 

Hello Friends -- Well...these LED tail lights were tricky but I think we solved the issue -- thank you all.

It turns out that once I had the 4 resistors in place and this did not help anything, I put everything back to stock configuration and started over.

Because I had also replaced the 3rd brake light with a modern LED unit, I decided to start with adding one 6 ohm resistor in parallel with the 3rd light. As luck would have it, this corrected the ATC code issue. I had all 4 LED halos connected with NO added resistors on any of these 4 fixtures. In the end all I needed was 1 resistor and this did the trick.

Why nothing helped with resistors attached to the Halo harness is not clear to me, but I am guessing that their on-board resistors + the added load resulted in an incorrect total resistance. Since the 3rd light did not have any resistor, this could have been why this worked.

Here are a few pics of how I mounted the resistor: I used an aluminum angle iron piece drilled to mount on the interior mounting stud. There was NO way I could drill through the box beam frame steel. I extended the resistor wires to reach the center light harness and spliced them in. This worked for me.




Resistor is to be mounted on metal to help dissipate the heat. These resistors get HOT.



Here is the side view. Note the the mounted bracket is not in contact with the car's brace - there is an air space between the back of the brace and the car's bracket.

 

Glad it all worked out!

 

Thanks very much for sharing your knowledge - really appreciate all the support here.